Leaching study of PNL 76-68 glass beads using the LLNL continuous-flow method and the PNL-modified IAEA method. Final report
Lawrence Livermore National Laboratory (LLNL) has conducted a long-term single-pass continuous-flow (SPCF) leaching test of the glass waste form PNL 76-68. Leaching rates of Np, Pu, and various stable elements were measured at 25/sup 0/ and 75/sup 0/C with three different solutions and three different flow rates. The purposes of the study were: (1) to compare SPCF leaching results with the results of a modified IAEA leach test performed by Pacific Northwest Laboratories (PNL); (2) to establish elemental leach rates and their variation with temperature, flow rate and solution composition; and (3) to gain insight into the leaching mechanisms. The LLNL and PNL leach tests yielded results which appear to agree within experimental uncertainties. The magnitude of the leach rates determined for Np and the glass matrix elements is 10/sup -5/ grams of glass/cm/sup 2/ geometric solid surface area/day. The rates increase with temperature and with solution flow rate, and are similar in brine and distilled water but higher in a bicarbonate solution. Other cations exhibit somewhat different behavior, and Pu in particular yields a much lower apparent leach rate, probably because of sorption or precipitation effects after release from the glass matrix. After the initial few days, most elements are leached at a constant rate. Matrix dissolution appears to be the most probable rate controlling step for the leaching of most elements.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 5141438
- Report Number(s):
- UCID-19492; ON: DE82021539
- Resource Relation:
- Other Information: Portions of document are illegible
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
36 MATERIALS SCIENCE
GLASS
LEACHING
NEPTUNIUM
PLUTONIUM
ACID CARBONATES
BATTELLE PACIFIC NORTHWEST LABORATORIES
BRINES
COMPARATIVE EVALUATIONS
DOPED MATERIALS
EXPERIMENTAL DATA
FLOW RATE
HIGH-LEVEL RADIOACTIVE WASTES
LAWRENCE LIVERMORE LABORATORY
MEDIUM TEMPERATURE
RADIOACTIVE WASTE PROCESSING
SIMULATION
SOLIDIFICATION
TEMPERATURE DEPENDENCE
VITRIFICATION
WATER
ACTINIDES
DATA
DISSOLUTION
ELEMENTS
HYDROGEN COMPOUNDS
INFORMATION
MANAGEMENT
MATERIALS
METALS
NATIONAL ORGANIZATIONS
NUMERICAL DATA
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
PROCESSING
RADIOACTIVE MATERIALS
RADIOACTIVE WASTES
SEPARATION PROCESSES
TRANSURANIUM ELEMENTS
US AEC
US DOE
US ERDA
US ORGANIZATIONS
WASTE MANAGEMENT
WASTE PROCESSING
WASTES
052001* - Nuclear Fuels- Waste Processing
360604 - Materials- Corrosion
Erosion
& Degradation